Notes from a know-it-all doctor's son:
Once you're infected, there's really nothing you can do but take care of yourself as best you can. Once flu symptoms appear, you can bet that you have been infected for at least a couple of days if not more. All of the symptoms, the fever, the pains, etc. are the effects of your body fighting the infection. If you have a sore throat, it's because your body has mounted a massive "search and destroy" mission to actually destroy more of your throat cells around the infection to keep the virus from using those cells to reproduce. It's an amazing mechanism, but causes us much discomfort.
Number 1 treatment: REST!!!!!!!!! your body needs all the energy it can muster to fight the disease, especially if you have fever. Use aspirin/tylenol/ibuprofen cautiously to relieve some pain.
Number 2: Plenty of fluids; chicken soup isn't a bad idea at all. Coca-cola syrup seems to work for stomach flu when nothing else will stay down. I keep compazine suppositories in the fridge for such an emergency.
Number 3: Tell everybody and all that are making any demands on you to f**k off. When you're sick, time to be selfish.
If any symptoms linger, be smart, see a doctor. As we get older lots of stuff settles in the lungs and can trigger opportunistic infections. It's a jungle out there!